使用反射和DRY原则优化代码

huangapple
go评论108阅读模式
英文:

Use of reflection and DRYing out some code

问题

我有一个函数，需要接收一个类型，确定子类型，然后创建子类型的副本。我一直盯着这个函数看，感觉可以简化，但就是想不出如何让它正常工作。以下是代码：

  1. func AddProp(prop prop, x, y int) []prop {
  3. 	v := reflect.ValueOf(prop)
  4. 	fmt.Printf("Prop类型是 %v", v.Type())
  6. 	switch v.Type() {
  7. 	case reflect.TypeOf(&Fence{}):
  8. 		f := Fence{}
  9. 		f.New(x, y)
  10. 		props = append(props, &f)
  11. 	case reflect.TypeOf(&Rock{}):
  12. 		f := Rock{}
  13. 		f.New(x, y)
  14. 		props = append(props, &f)
  15. 	}
  16. 	return props
  17. }

实际上，代码比这个要长得多，有更多的情况。谢谢你的帮助！

编辑：
很合理的问题 - 什么是 prop？

  1. type prop interface {
  2. 	New(int, int)
  3. }

第二次编辑：
我的结构体看起来像这样：

  1. type Prop struct {
  2. 	fullImage image.Image
  3. 	x, y int
  4. }
  5. type Fence struct {
  6. 	Prop
  7. 	horizontal bool
  8. }

我已经为两者定义了 New(x, y int) 方法：

  1. func (p *Prop) New(x, y int)
  2. func (p *Fence) New(x, y int)

我需要获取 Fence 结构体并基于 Fence 而不是 Prop 调用 New 方法。

英文:

I have a function that needs to receive a type, determine the subtype, then create a copy of the subtype. I keep staring at this function and I feel this can be simplified, but I just can't figure out how to get it functioning. Here's the code:

  1. func AddProp(prop prop, x, y int) []prop {
  3.   v := reflect.ValueOf(prop)
  4.   fmt.Printf("Prop type is %v", v.Type())
  6.   switch v.Type() {
  7.   case reflect.TypeOf(&Fence{}):
  8.   	f := Fence{}
  9.   	f.New(x, y)
  10.   	props = append(props, &f)
  11.   case reflect.TypeOf(&Rock{}):
  12.   	f := Rock{}
  13.   	f.New(x, y)
  14.   	props = append(props, &f)
  15.   }
  16.   return props
  17. }

It's actually quite a bit longer than this with many more cases. Thank you for taking a look!

Edit:
Perfectly reasonable question - what is a prop?

  1. type prop interface {
  2. 	New(int, int)
  3. }

Second Edit:
My structs looks like this:

  1. type Prop struct {
  2. 	fullImage image.Image
  3. 	x, y int
  4. }
  5. type Fence struct {
  6. 	Prop
  7. 	horizontal bool
  8. }

I have New(x,y int) defined for both

  1. func (p *Prop) New(x, y int)
  2. func (p *Fence) New(x, y int)

I need to get the Fence struct and call the New based on the Fence and not the Prop

答案1

得分: 0

你可以简化这段代码，前提是所有类型都有New方法：

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"reflect"
  6. )
  8. func main() {
  10. 	props := AddProp(&Rock{}, 1, 1)
  11. 	fmt.Printf("%#v\n", props)
  13. 	props = AddProp(&Fence{}, 1, 1)
  14. 	fmt.Printf("%#v\n", props)
  16. }
  18. type Rock struct{}
  20. func (r *Rock) New(x, y int) {}
  22. type Fence struct{}
  24. func (r *Fence) New(x, y int) {}
  26. type prop interface {
  27. 	New(x, y int)
  28. }
  30. func AddProp(p prop, x, y int) (props []prop) {
  31. 	newValue := reflect.New(reflect.TypeOf(p).Elem()).Interface()
  32. 	z := newValue.(prop)
  33. 	z.New(x, y)
  34. 	props = append(props, z)
  35. 	return props
  36. }
英文:

You can simplify this provided all types have the New method:

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"reflect"
  6. )
  8. func main() {
  10. 	props := AddProp(&Rock{}, 1, 1)
  11. 	fmt.Printf("%#v\n", props)
  13. 	props = AddProp(&Fence{}, 1, 1)
  14. 	fmt.Printf("%#v\n", props)
  16. }
  18. type Rock struct{}
  20. func (r *Rock) New(x, y int) {}
  22. type Fence struct{}
  24. func (r *Fence) New(x, y int) {}
  26. type prop interface {
  27. 	New(x, y int)
  28. }
  30. func AddProp(p prop, x, y int) (props []prop) {
  31. 	newValue := reflect.New(reflect.TypeOf(p).Elem()).Interface()
  32. 	z := newValue.(prop)
  33. 	z.New(x, y)
  34. 	props = append(props, z)
  35. 	return props
  36. }

huangapple
  • 本文由 发表于 2021年8月4日 21:59:20
  • 转载请务必保留本文链接：https://go.coder-hub.com/68652630.html
  • dry
  • go
  • reflection
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